Turns out, they amount to more than just a hill of beans. Dry beans are a sustainable crop as they can be grown with less irrigation and fertilizer than many other crops, are a good rotation crop due to their nitrogen fixing capabilities (up to 40 lb∙acre−1), and can break some common disease cycles (such as Verticillium wilt caused by Verticillium dahliae Kleb.). Dry beans are also important in the human diet and are a good source of protein (18%–22%), dietary fiber, minerals (such as potassium, zinc and iron) and B vitamins (such as folic acid and B12).

There is small-scale production of dry beans in Northwest Washington, where they have been grown organically on a small scale for over 100 years. Regional heirloom dry bean varieties include a wide diversity of market classes, including navy, black, pinto and unique color-patterned types. Currently, in Northwest Washington, organic heirloom and color-patterned varieties are sold at regional farmers markets for $4 to $12 per lb.

Grower experience suggests that local heirloom dry bean varieties are well adapted to the Northwest Washington climate; however, available varieties have not been previously evaluated in systematic trials. It is common practice for farmers in the region to grow dry beans without irrigation, as the presence of heavy dew—combined with precipitation and relatively low temperatures during the summer months—provides adequate moisture for crop production most years.

There is high demand for local organic crops, and demand for organic and nutritious staple crops has opened a market opportunity for dry beans. In western Washington, locally-grown dry beans are sold at farmers markets, as well as to institutions (schools, hospitals, etc.). Cooking time is important to consumers who are purchasing beans in the dry form, especially for institutions such as schools that prepare large quantities of beans. The protein content of heirloom dry bean varieties is also generally unknown in comparison to newer varieties.

In this study, dry bean varieties that have been grown in Northwest Washington for 20 to 130 years were compared to standard varieties (seed grown outside the region) in the same market class, to determine which may be best suited for organic production in this region. Varieties were also measured for cooking time and protein content, as these are important considerations for consumers.

Materials and Methods
The experiment was carried out at Washington State University (WSU) Northwestern Washington Research and Extension Center (NWREC) at Mount Vernon. The field site was transitioned to certified organic during the study and was eligible for organic certification in fall 2014. The experiment included four replications and was repeated two years (2013 and 2014).

Plots were four rows wide and 3 m in length. Heirloom varieties were collected from growers in five counties (Clallam, Island, San Juan, Skagit and Whatcom) in Northwest Washington where they had been grown at each site as early as 1880 and as recently as 1990. A total of 13 heirloom (H) varieties were collected and planted in the first study year, each matched as closely as possible with a standard (S) variety in the same market class (Table 1); however, four heirloom varieties did not germinate well or had a climbing growth habit in the field plots and, so, were dropped from the study. A total of 20 dry bean varieties were included both years: 9 heirloom and 11 standard varieties.

Beans were hand seeded 22 May 2013 and 15 May 2014. Both years, spacing in the row was 5 cm, and seeding depth was 5cm. Rows were spaced 76 cm center-to-center in 2013 and 86 cm in 2014; spacing between rows was increased in the second year to provide better tractor access for cultivation to control weeds. Both years, the seed was inoculated with a granular Rhizobium spp. blend. Plots were side dressed with organic fertilizer (Proganic 8-2-4) 21 days after planting (DAP) at a rate of 46 lb N· acre−1 in 2013 and 54lb N· acre−1 in 2014. For weed control, tractor cultivation was done between rows with a 2-headed rototiller 6 and 21 DAP in 2013 and 14 and 36 DAP in 2014. In 2014, to reduce in-row weed pressure, plants were hilled (2–3 in.) 41 DAP with 10-in. discs mounted on a cultivation tractor. Hand weeding was done within rows 42 and 75 DAP in 2013 and 53 DAP in 2014. The study was not irrigated either year.

The center three feet of the middle two rows in each plot was harvested by hand when beans in the plot were dry, but before pod shatter; days to harvest (DTH) were calculated for each variety. Plants from each plot were placed in a burlap sack and dried at 106 °F for 36 hours or until the stems snapped and bean seed moisture content was approximately 12%. Whole dry plants were fed through a chipper-mulcher that had been converted to a small-scale standing thresher (see vegetables.wsu.edu/dryBeans.html). Bean cooking time, firmness and protein content were measured 6 months after harvest in 2013 and 2014.

Results

Overall for both years, heirloom varieties were harvested three days earlier than standard varieties (110 DTH and 113 DTH, respectively)(Table 2). The average for all varieties was 113 DTH (13 September) in 2013 with a range of 104–127 DTH, as compared to 110 DTH (2 September) in 2014 with a range of 106–118 DTH. While the overall mean air temperature for the growing season was similar both years (61 °F in 2013 and 63 °F in 2014), accumulated growing degree days (GDD) for the growing season were slightly lower in 2013 (1490 GDD) as compared to 2014 (1524 GDD).

Varieties with the shortest DTH both years were “Bale” (H), “Coco” (H), “Decker” (H), “Ireland Creek Annie” (H), “Ireland Creek Annie” (S), “Kring” (H) and “Rockwell” (H); while varieties with the longest DTH both years were “Eclipse” (S), “Hutterite” (S) “Skyriver” (H), “Youngquist Brown” (H) and “Orca” (S). Overall yield of heirloom varieties (1653 lb·acre−1) was similar to yield of standard varieties (1771 lb·acre−1). Mean yield for all varieties was significantly greater in 2013 (2025 lb·acre−1) than in 2014 (1451 b·acre −1). Varieties that were high yielding both years were “Eclipse” (S), “Lariat” (S) and “Youngquist Brown” (H); while only “Calypso” (S) was low yielding both years.

While there were 11% more plants per acre in 2013 than in 2014 (approximately 106,477 and 94,332 plants per acre, respectively), due to different between-row spacing each year (30 in. and 34 in., respectively), yield was 30% greater in 2013. There was little difference in mean temperature for the growing season both years (61 °F and 63 °F, respectively), and while precipitation was essentially equal both years (9.1 in. and 9.8 in., respectively), there was no rainfall in July 2013, while there was 1.26 in. of rainfall in July 2014. The result from this study suggests that optimal planting density needs to be determined in Northwest Washington; however, in organic production systems row spacing must be adequate to allow for mechanical weed control, and thus, plant population is likely to be determined by equipment needs and not yield optimization.

Cooking time measured with the MBC for heirloom varieties (26 min) was similar to standard varieties (22 min) (Table 2). Only “Eclipse” (S) had the shortest cooking time both years, while “Rockwell” (H), “Silver Cloud” (S) and “Soldier” (S) had short cooking time in 2013, and “Orca” (S) and “Youngquist Brown” (H) had short cooking times in 2014 (Figure 2). “Coco” (S) had the longest cooking time both years, while “Etna” (S) and “Skyriver” (H) also had long cooking times in 2013. While cooking time measured with an MBC is shorter than with most home-cooking methods, it does provide relative values for comparison purposes.

Overall, firmness after cooking with the MBC also did not differ between heirloom varieties (8.0 N) and standard varieties (7.4 N)(Table 2). Bean varieties with the lowest firmness both years were “Eclipse” (S) and “Hutterite” (S), while only “Soldier” (S) had the greatest firmness both years. Protein content for heirloom varieties (20.3%) was similar to standard varieties (20.7%) (Table 2). Varieties with the highest protein both years were “Calypso” (S), “Coco” (S) and “Silver Cloud” (S), while “Hutterite” (S) and “Youngquist Brown” (H) had the lowest protein both years.

Discussion
The most important consideration when selecting a dry bean variety for a cool region, such as Northwest Washington is the number of days to harvest (DTH). DTH in this study were 22 days longer than in other bean-growing regions. In this study, Northwest Washington heirloom varieties matured three days earlier than standard varieties, and six heirloom varieties had the shortest DTH both years. This difference could be significant as rainfall starting in mid to late September can prevent beans from reaching a sufficiently dry stage for harvest and storage. Studies of early maturing varieties are needed to determine if there are standard varieties well suited to this region.

Overall yield of dry beans in this study was 1,741 lb·acre−1, which was comparable to yield in one organic field study in Michigan (1,705 lb·acre−1, non-irrigated), but less than a different organic field study in Michigan (2,192 lb·acre−1, irrigated), as well as conventional field studies in Idaho (3,094 lb·acre−1, irrigated) and North Dakota (2,359 lb·acre−1, non-irrigated). Nevertheless, this study demonstrates that dry beans can be a productive crop in Northwest Washington, even without irrigation, and, therefore, could be a suitable legume crop for crop rotation in the region.

Consumer demand for regionally-produced staple crops has opened a market opportunity such as with dry beans. While there are many dry bean varieties that can be grown successfully in the region, consumers who shop at farmers markets (as well as other direct market customers) may be more likely to purchase unique color-patterned beans or heirloom varieties. These niche market varieties may be sold at premium prices ($4–$12 per lb).

While not as profitable, schools could be secure and substantial customers for local crops, including dry beans. The National School Lunch Program (NSLP) requires school cafeterias to serve ½ cup dry beans and/or dry peas per student per week; in Northwest Washington where 530,000 students are enrolled in NSLP, this equates to 112,435 lb of dry beans served in school cafeterias per week or 2,200 tons per year (based on a school year of 36 weeks). For institutional buyers, it is likely that price is the most important decision-making factor, so identifying the highest yielding cultivars regardless of appearance may be a priority for this market outlet.

Varieties that are faster cooking may be of particular interest to institutions where large quantities of beans are prepared. Cooking time measured with the MBC is shorter than can be obtained with most home cooking methods, and the MBC underestimates cooking time as beans are generally too firm for eating. However, the MBC provides a comparative cooking time and may be used to identify beans that are fast or slow cooking. Of the beans with the shortest cooking time in this study, “Eclipse” (S) was the only variety that was among the softest after cooking. In contrast, “Silver Cloud” (S) and “Rockwell” (H) both had a shorter cooking time, but their beans were among the most firm after cooking.

Protein content of dry bean varieties is also of interest to many consumers. The mean protein content for dry bean varieties in this study was 21% with a range of 17%–26%. One serving (1/2 cup or 96 g dry uncooked beans) of a high protein variety contains 24g of protein, and one serving of a low protein variety contains 16 g of protein. In order to acquire the same amount of protein when eating a low protein bean variety, an additional 8 g of beans are needed, or the equivalent of approximately 10 dry uncooked beans, or approximately two spoonfuls. While this amount could be considered insignificant for a household, for institutions, such as schools in Northwest Washington, this would amount to an additional 11,684 lb of dry beans per week or 210 tons per year; for this purpose, the selection of dry beans with high protein may be desirable.

This study shows that dry beans have the potential to be grown as a commercial organic crop in Northwest Washington; however, other considerations that must first be addressed in the region are equipment needs for mechanical harvest, drying and cleaning. Additionally, a cooking and packaging facility is likely needed for the school market, as soaking and cooking dry beans in school kitchens is currently perceived as a barrier by school food service staff. Existing facilities, such as grain dryers, may be suitable for drying beans for long-term storage, and vegetable processing plants in the region may be suitable for cooking and canning the beans; however, these would need to be tested to ensure suitability for dry beans.

Carol Miles is a professor in the Department of Horticulture at the Washington State University Northwestern Washington Research and Extension Center, Mount Vernon, WA. Kelly Ann Atterberry is a former M.S. graduate student
in Horticulture (graduated May 2015) and Brook Brouwer is a former Ph.D. graduate student in Crop and Soil Sciences (graduated August 2015), at WSU, Northwestern Washington Research and Extension Center, Mount Vernon.

Acknowledgments
We thank Ed Scheenstra, Ron Dralle, Jesse Wimer, Charlene Grahn and Carolyn Klismith for their assistance. Funding for this project from American Pulse Association, Northwest Agriculture Research Foundation and Washington State University Center for Sustaining Agriculture and Natural Resources is gratefully acknowledged.